Paiche, also known as arapaima, can grow to 500 pounds in shallow, muddy waters in the Amazon. It is a popular fish in South America that’s endangered because of overfishing and deforestation. In Brazil, the commercial catch of the wild fish is banned.

But Sushi Samba in New York, Ocean in Miami and La Mar in San Francisco are serving farm-raised paiche with the help of CleanFish, a company that works with small producers to distribute sustainably harvested and farm-raised seafood. The fish is farmed by a private company, Amazone, that’s a division of a Peruvian conglomerate.

Paiche is now on the $33 prix fixe Restaurant Week dinner menu at both locations of Sushi Samba, and may stay on the menu later. Fernando Navas, the corporate chef of the Japanese-Latin fusion restaurants, is offering a miso-jalapeno glazed paiche with a mizuna and blood orange salad. He leaves the skin on before pan searing the fish, which has similar texture to cod and Chilean sea bass.

Mr. Navas first tasted paiche three months ago at Malabar, a high-end restaurant in Lima, Peru. The fish had a delicate texture and few bones, he said, adding that he was impressed by its versatility.

“It was a very strange form of fish when I saw a picture,” said Mr. Navas, who paid about $14 to $15 a pound for the fish, which is similar to Chilean sea bass. “I think it’s very exotic looking and better to eat.”

Alisha Lumea, a spokesperson for CleanFish, said: “The production is not very high right now. A big part of the project is to protect the species while introducing it to more people.”